The present invention relates to a process for Grignard type reactions comprising mixing at least two fluids in a microreactor.
Grignard type reactions are very important reactions in preparative chemistry. In general, a Grignard type reaction is the reaction of compounds of formulaR1—Mg—X  (I),orR1—Mg—R1  (II)wherein R1 is selected from the group consisting of alkyl, cycloalkyl, alkenyl, alkynyl, aryl and aralkyl, and wherein X is a halogen atom selected from the group consisting of chlorine, bromine and iodine, with a compound of formulaR2—X  (III),wherein R2 is alkyl, cycloalkyl, alkenyl, alkynyl, aryl and aralkyl, and X is halogen; or with a compound containing a polar multiple bond like C═O, C═N, C≡N, C═S, N═O and S═O. The compound of formula I is called the Grignard reagent. Other uses of the compounds of formulae I or II are the exchange of halogen atoms of boron, silica, tin or antimony compounds or the preparation of highly reactive Grignard compounds which are otherwise hard to obtain.
Performing Grignard reactions using single micro mixers is disclosed in EP-A-1285924. The disclosed method is not applicable to industrial scale productions.
A persistent aim of the chemical industry is to constantly improve and control chemical reactions. Greater control over reactions may lead to, for example, improvements in safety, increase in reaction product yield and/or purity, or the isolation of valuable highly reactive intermediate products. In particular, greater control over reagent mixing, fluid flow, heat sinking/sourcing and catalytic efficiency is desirable.
A general method which provides such improved control over reactions would therefore be advantageous. Particularly, methods for performing exothermic reactions in large scale in a controlled manner are sought-for.